From f6601f3af4096b593a7f010b17737b97747b9a46 Mon Sep 17 00:00:00 2001 From: Tom Wood Date: Tue, 25 Aug 1992 20:13:49 +0000 Subject: [PATCH] entered into RCS From-SVN: r1945 --- gcc/rtl.def | 22 ++++++++++++---------- 1 file changed, 12 insertions(+), 10 deletions(-) diff --git a/gcc/rtl.def b/gcc/rtl.def index 17b9715..cdbfba6 100644 --- a/gcc/rtl.def +++ b/gcc/rtl.def @@ -236,7 +236,7 @@ DEF_RTL_EXPR(DEFINE_DELAY, "define_delay", "eE", 'x') Each gives a set of operations and associated delays. The first three operands must be the same for each operation for the same function unit. - All delays are specified in units of COST_PER_CYCLE. + All delays are specified in cycles. 1st operand: Name of function unit (mostly for documentation) 2nd operand: Number of identical function units in CPU @@ -250,19 +250,21 @@ DEF_RTL_EXPR(DEFINE_DELAY, "define_delay", "eE", 'x') executing this operation. The meaning depends on whether or not the next operand is supplied. 7th operand: If this operand is not specified, the 6th operand gives the - cost of scheduling another operation on this unit while a - previous one is active. A value of zero should be used for a - pipelined unit. If only one operation can be executed a time - and the unit is busy for the entire time, the 3rd operand - should be specified as 1 and the 6th and 7th operands will - be ignored. + number of cycles after the instruction matching the 4th + operand begins using the function unit until a subsequent + insn can begin. A value of zero should be used for a + unit with no issue constraints. If only one operation can + be executed a time and the unit is busy for the entire time, + the 3rd operand should be specified as 1, the 6th operand + sould be specified as 0, and the 7th operand should not + be specified. If this operand is specified, it is a list of attribute expressions. If an insn for which any of these expressions is true is currently executing on the function unit, the - delay will be given by the 6th operand. Otherwise, the - insn can be immediately scheduled (subject to the limit on - the number of simultaneous operations executing on the + issue delay will be given by the 6th operand. Otherwise, + the insn can be immediately scheduled (subject to the limit + on the number of simultaneous operations executing on the unit.) */ DEF_RTL_EXPR(DEFINE_FUNCTION_UNIT, "define_function_unit", "siieiiV", 'x') -- 2.7.4